Open and closed metal vessel with which to hold metals hot and to melt them, and for transporting said liquid metals

ABSTRACT

The open and closed metal vessel  1   a   , 1   b   , 1   c   , 1   d  serving to hold hot and to melt metals and to transport said liquid metals comprises an open and closed cavity  11  which is subtended by thermally insulating materials  3, 3   a   , 3   b   , 3   c   , 3   e   , 3   f  and which is seamlessly lined by an integral, exchangeable, single-layer or stratified textile, 3D-surface structure  4 . Said metal vessel receives the liquid and solid metal to hold it hot or to melt it and also serves to transport the liquid metals. The heating to hold hot and to melt the metals is implemented by heater elements  6, 7  situated in the liquid metal and furthermore by heater elements  8  configured underneath the 3D-surface structure, or by induction. ( 9, 10 ). The closed metal vessel  1   b  is equipped with an integral, displaceable furnace riser pipe  20  on the furnace cover  16 . When casting, the open metal vessel  1   a   , 1   c  may serve as a hot-holding, ladling and melting furnace and the closed metal vessel  1   b   , 1   d  may serve as a transport receptacle, all described operational criteria being met by exchanging the furnace cover or removing it and using the open and closed metal vessel  1   a   , 1   b   , 1   d.

[0001] The present invention relates to an open and closed metal vessel of the kind defined in the preamble of claim 1 serving to hold metals hot and to melt them, further to transporting such liquid metals.

[0002] Displaceable as well as fixed-shape crucibles are used to hold metals hot and to melt them.

[0003] Displaceable crucibles illustratively are made of clay-graphite, silicon carbide, cast iron, cast steel or metal plate, depending on casting materials to be held hot or be molten. They are used in hot holding furnaces or in melting furnaces. Heating can be carried out by means of electrical resistors, induction or gas. Heat transfer to the liquid or solid metal in the crucible through the furnace space or, in the event induction is used, directly through the crucible wall, will entail substantial wear due to thermal, mechanical and chemical stresses on the crucibles being used. Moreover, where electrical resistance or gas heating is used, large energy consumption is required to heat the furnace space and the crucible, as well as being incurred by the heat dissipation taking place at the refractory furnace lining. Illustratively the German patent document 29 17 577 A1 discloses a heat-resistant collecting vessel for the leakage melt and switch elements detecting said melt, while the European patent document 0 895 490 B1 and the German patent document 198 02 342 describe a crucible furnace for low-pressure casting or for filling the pressurized chamber of a horizontal and vertical cold-chamber of a pressure die casting machine.

[0004] Permanently integrated crucibles constitute a permanent part of the furnace. Typically they consist of chamotte brick masonry with a stamped or cast refractory lining. Because of the masonry thickness, the liquid-melting heating in the furnace is carried out inductively. This design incurs the substantial drawback that the induction channel—in particular as regards aluminum alloys—depending on flow rate of the metal, may already be clogged after about 2 weeks because of the adhesion of the oxides and nitrides and thus shall block said flow. In order to (re)open the said induction channel, most of the time the casting furnace must be exchanged, the residual melt must be removed, and said channel must be pried open using a compressed air hammer. Also the furnace outside surface temperatures run to 70 to 100EC while being as high as 120EC in the region of the induction channel. This closed furnace system is used especially for low pressure casting.

[0005] The objective of the present invention is avoid said known drawbacks by proposing an open and closed metal vessel to hold hot, and to melt metals and to transport said liquefied metals, said container being free from a crucible whether, under the conventional definitions, said crucible either is displaceable or permanently integrated.

[0006] To attain this goal, the open and closed metal vessel is constituted by a housing at the inside of which thermally insulating materials subtend an open or closed cavity lined with a textile 3D-surface structure, the closed metal vessel being fitted with a displaceable riser pipe. Advantageous embodiment modes and further developments of the invention are stated in the dependent claims.

[0007] When, in its open mode, the open and closed metal vessel of the present invention may serve as a hot-holding, scooping and melting furnace, whereas in its closed mode, it may serve as a hot-holding furnace, a low-pressure casting furnace, a low-pressure metal transporting furnace and as a liquid-metal, transporting container.

[0008] The open and closed metal vessel of the present invention comprises an integral 3D-surface structure lining which covers in seamless manner the open and closed cavity of the metal vessel to receive the liquid or solid metal and it is further fitted with discharge channels and covering surfaces. This goal is attained by the high flexibility of said structure and its versatility in assuming many geometric and spatial configurations. This integral, textile 3D-surface structure may be used as a single layer or a multi-layer to line and cover cavities and surfaces. By coating the single or multilayer surfaces of said 3D-surface structure, and depending on the requirements set on the said liquid or solid metals, the thermal, chemical as well as mechanical properties of said metals may be additionally enhanced. In a further advantageous embodiment of the present invention, the thermally insulating material enclosing said textile structure's inside and outside surfaces is designed to be a seamlessly upwardly open insulation housing.

[0009] In order to preclude chemical and/or electrical reactions, the heater elements inserted into the liquid metal(s) are clad by appropriate protective substances. Said heater elements are configured underneath the said textile structure and are protected by a thin and exchangeable plate against leakages of liquid metals.

[0010] The integral, displaceable furnace riser pipe affixed to the closed metal vessel is made to pass through, and be centered relative to, a bush. Said furnace riser pipe is displaceably connected to a drive system which implements the openings and closings related to continuously filling with liquid metals both metallic and non-metallic casting and furthermore to filling pressure chambers molds with said liquid metal(s).

[0011] In order to assure the greatest possible safety of operation, the closed metal vessel shall be additionally placed within a sealable single or multiple container when liquid metal must be transported.

[0012] Claim 5 cites wear-resistant, flexible materials to be used for the textile, 3D-surface structure, whereas claim 7 lists effective thermally insulating materials and claim 8 cites protective substances for the heater elements inserted into the liquid metal and configured underneath the textile 3D-surface structure. The just above cited advantages as well as further ones are discussed below in relation to the preferred embodiment of the present invention and in relation the appended drawings.

[0013]FIG. 1 is a cross-section of an open metal vessel of the invention,

[0014]FIG. 2 is a cross-section of a closed metal vessel of the invention fitted with a displaceable riser pipe,

[0015]FIG. 3 is a cross-section of an open metal vessel of the invention used to melt metals, and

[0016]FIG. 4 is a cross-section of a closed metal vessel of the invention used for transporting liquid metal.

[0017] The open metal vessel of FIG. 1 shows an aperture 12 which passes through the textile 3D-surface structure 4 and is used to fill the cavity 11 with liquid and solid metals and also to remove liquid metal for casting. The heating to hold hot and to melt liquid and solid metals in this embodiment can be implemented by heater elements 6, 7 8 or by induction 9. Accordingly the open metal vessel 1 a may serve as a hot-holding, ladling and melting furnace for casting operations.

[0018]FIG. 3 shows another open metal vessel 1 c to melt metals by means of an inductive heater 10 and fitted with a discharge channel 13 for the liquid metal.

[0019] The closed metal vessel 1 b of FIG. 2 has been filled with a liquid metal 18 in its cavity 11 and comprises both a hermetically sealing furnace cover 16 which, jointly with said container's thermally insulating lining 3 c and the surface of the liquid metal, subtends a gassing space 17, and the furnace riser pipe 20 connected to the control system 23 assuring the vertical opening and closing steps between said pipe and the casting mold 22. The bush 21 mounted on the furnace cover 16 guides and centers the displaceable furnace riser pipe 20. This advantageous design allows rapidly and simply exchanging the furnace(s) used in casting. In this instance the liquid metal also may be heated by the heater elements 6, 7, 8 or by induction 9. In this manner the closed metal vessel 1 b may serve as a low pressure casting furnace or a low-pressure metal transporting furnace to fill casting molds or pressure chambers for pressurized casting and also to hold metals hot in casting operation.

[0020]FIG. 4 shows another closed metal vessel 1 d for transporting liquid metals in a closable single or multi-container 28. To preclude the liquid metal from sloshing while being transported, the thermally insulating material 3 f lining the inside space of the transport container's cover 25 comprises a cone dipping into the liquid metal. With this design the metal container 1 d serves directly as a hot-holding furnace for metal buffering in casting plants and furthermore—on account of said exchanging or removing said furnace cover—as a hot-holding, ladling, melting furnace, a low-pressure casting furnace and a low-pressure metal transporting furnace, the heating of the liquid metals optionally being implemented by insertable heater elements 6, 7 or by stationary, pre-installed heater elements 8 or by induction 9.

[0021] The inventive open and closed metal vessel 1 a, 1 b, 1 c, 1 d may be manufactured in all possible geometric shapes, the outer casing 2 subtending the inner space in turn subtending by means of the thermally insulating materials 3, 3 a, 3 b, 3 c, 3 f and by the textile 3D-surface structure 4, an open and closed cavity 11 receiving the liquid or solid metal which it shall hold hot or implement melting it or it shall transport the liquid metal.

[0022] The high flexibility and tear-resistance of the textile 3D-surface structure 4 allows seamlessly lining the cavity 11, the discharge channel 13 and the cover surfaces 2′, 3′, 3 a′, where movable pins 14 or fixed pins 15 affix the textile 3D-surface structure 4 in its position. Because the liquid metal may be drained from the open metal vessel 1 a, 1 c or from the metal vessel 1 b, 1 d to be opened, exchanging the textile 3D-surface structure 4 can be carried out in a brief time. Another advantage regarding the textile 3D-surface structure 4 is its collapsibility and its low weight, said features being substantial advantages as regards their storage and transportation. Because of the high thermal strength of the textile 3D-surface structure 4, pre-warming time intervals or slow heating rates of the open and closed metal container 1 a, 1 b, 1 c, 1 d are not required.

[0023] In order to further reduce heat losses due to convection, the invention comprises the upwardly open insulation housing which is made of seamless, thermally insulating materials 3, 3 b, the material 3 consisting of a cast glass foam and the thermal insulation 3 b is made of fiber ceramics withstanding high compressive loads. These features and the optimal heat barrier represented by the open and closed melt vessels 1 a, 1 b, 1 c, 1 d allow mounting the heater elements 6, 7, 8 directly in or at the cavity 11, the heater elements 8 being protected against leakage of metal liquid by a thin and exchangeable plate 3 d. On account of this direct and also indirect transfer of heat to hold hot and melt metals, it is possible to preclude metals from overheating and thus exclude the otherwise entailed adverse chemical reactions as well as increased gas absorption.

[0024] In order to preclude transported liquid metal from sloshing, the inside space of the cover 25 of the closed metal container 1 d is lined with a conical heat insulating material 3 f dipping into the liquid metal. Be it further borne in mind that details relating to design which may entirely differ from those disclosed above may shall fall within the scope of the present invention. 

1. An open and closed metal vessel for holding hot and melting metals and to transport said liquid metals and comprising heater elements (6, 7, 8) or being fitted with inductive heaters (9, 10), characterized in that the open and closed metal vessel (1 a, 1 b, 1 c, 1 d) in the inside space of which thermally insulating materials (3, 3 a, 3 b, 3 c, 3 e, 3 f) subtend an open or a closed cavity (11) which is lined with a textile 3D-surface structure (4), and that the closed melt vessel (1 b) comprises a displaceable furnace riser pipe.(20).
 2. Open and closed metal vessel as claimed in claim 1, characterized in that the open metal vessel (1 a, 1 c) may serve as a hot-holding, ladling and melting furnace and that the closed metal vessel metal vessel (1 b, 1 d) may serve as hot-holding furnace, low-pressure casting furnace, low-pressure metal transporting furnace and as a liquid-metal transporting vessel.
 3. Open and closed metal vessel as claimed in either of claims 1 and 2, characterized in that the integral textile 3D-surface structure (4) lines in seamless, single-layer or stratified manner the cavity (11), the discharge channels (13) and the cover surface (2′, 3′, 3 a′).
 4. Open and closed metal vessel as claimed in either of claims 2 and 3, characterized in that the surfaces of the single-layer or stratified textile 3D-surface structure (4) comprise(s) a coating depending on metal requirements.
 5. Open and closed metal vessel as claimed in either of claims 3 and 4, characterized in that the textile 3D-surface structure (4) is made of glass or ceramic fibers.
 6. Open and closed metal vessel as claimed in claim 1, characterized in that the thermally insulating material (3, 3 b) subtending the inside space of the metal vessel is a seamless, upwardly open insulating housing.
 7. Open and closed metal vessel as claimed in either of claims 1 and 6, characterized in that the thermally insulating materials (3, 3 a, 3 b, 3 c, 3 e, 3 f may be glass foam, glass fibers, ceramic or fiber-ceramic materials.
 8. Open and closed metal vessel as claimed in claim 1, characterized in that the protective substances of the heater elements (6, 7, 8) mounted in the metal vessel (1 a, 1 b, 1 d) may be made of glass, glass fibers and fiber ceramics.
 9. Open and closed metal vessel as claimed in claim 1, characterized in that the integral, displaceable furnace riser pipe (20) is both centered and guided by a bush (21) on the furnace cover (16) and is displaced by a drive system (23).
 10. Open and closed metal vessel as claimed by claim 1, characterized in that the closed metal vessel (1 d) is received by an additional, sealable single or collecting container (28). 